The present invention concerns a composition for the treatment of burns, sunburns, abrasions, ulcers and cutaneous irritation. More specifically, the invention relates to a preparation for topical administration having analgesic, antiseptic and skin healing promoting activity. The preparation is particularly suitable for the treatment of burns, scalds and sunburns, and is useful in general in the treatment of any alteration of the dermal tissue that may require the reactivation of the epithelisation processes.
As it is known, the exposure to an excessive heat of any kind causes on the human epidermis, and often also on the underlying tissues, situations of pathological alteration and lesions the seriousness of which varies according to the duration and the intensity of the exposure, and to the sensitivity of the single individual. Real burns or scalds may be caused, for instance, by the contact with hot matter or articles, such as flames, hot liquids or burning bodies, or also by an excessive exposure to radiation sources, including the sun. According to the current clinical classification, a burn may be of first, second or third degree, depending upon the gravity of the lesion. The first-degree burns are limited to the superficial layers of the epidermis and are characterised by local erythema (redness) and light edema (swelling); the second-degree burns involve a damage extended to the dermis, more marked edema and formation of blisters containing serous exudate, and the third-degree burns are accompanied by a true destruction of the structural elements of the skin, with formation of blisters, sores and the presence, in the most serious cases, of charred zones. In the most critical cases the involvement is extended to general phenomena, such as shock, acute intoxication and anaemia.
Reactions quite similar to the ones described above may be produced by the contact with aggressive chemical agents, such as concentrated acids or alkalis, or by electrical discharges. Likely, albeit less serious, reactions may also originate from the contact of the skin with animal secretions or stinging plants, such as jellyfish stings or insect bites. Irritation, redness, itching and, sometimes, blister formation may also be caused by an intense rubbing of the skin, while a stronger rubbing may give rise to abrasions and grazes. Lastly, another quite common group of pathologies affecting the superficial tissues are ulcerous-dystrophic alterations, such as torpid sores, decubitus or bed-sore, varicose or stasis ulcers and rhagades.
In all of the cases presented above, in agreement with the various levels of severity, recourse is made to the topical administration of remedies that should exert a range of different actions, including an analgesic action, a stimulating action on the reparative processes of the skin tissues, i.e. an action promoting healing of the lesions, an anti-inflammatory action and, moreover, an antiseptic action, in order to prevent the occurrence of secondary infections on the affected zones. Actually, the injured tissues are particularly prone to the development of infections, which obviously hinder a rapid and complete healing of the skin.
A product for topical application known to be particularly useful for the treatment of burns, scalds and sunburns, as well as for the treatment of other affections of the superficial tissues such as the disorders and injuries mentioned above, is the ointment sold in Italy under the trademark Foille(copyright) (Synthelabo). The latter contains four different active ingredients, i.e., benzocaine, benzyl alcohol, 8-hydroxy-quinoline and colloidal sulphur. The first two ingredients have anaesthetic properties, the third one is an antiseptic and the fourth one enhances the formation of stratum corneum (horny layer).
In the use of the above and of other possible remedies against burns, a timely application is extremely important. It may be anticipated that the therapy will be the more effective the shorter is the time elapsed between the event that caused the lesions and the application of the remedy on the said lesions. Suitable products may be in the form of ointments or salves, creams, emulsions, gels, foams, sprays or medicated dressings or bandages, which must be directly applied on the affected zone and must be kept into contact with the lesion, if necessary by soaking the dressing from the exterior with further product, until the reparative process is seen to stably proceed.
In such situations it would be desirable that the recovery time be as short as possible, not only because this reduces the pain or discomfort caused to the patient, but also because the longer the lesion remains exposed to the environment the higher is the risk of secondary infections. As pointed out in the foregoing, the latter obviously slow down or negatively affect the recovery process. In view of that, it is extremely important that a preparation for the treatment of skin lesions such as burns and the like be highly active in promoting the regeneration of the injured tissues, thus enhancing the healing process.
A product which is known to possess the above properties, and which may be used to formulate a medicament suitable for the treatment of burns and of other lesions of the skin is chlorophyll (see Merck Index, 11th ed., 1989, Merck and Co. Inc., monograph No. 2155).
As it is known, chlorophyll is the green pigment of plants, contained in various proportions and types also in algae. The said pigment plays a primary role in the vegetal metabolic activity known as photosynthesis. The chlorophyll molecule, in its variants a, b, c and d,is characterised by an active nucleus known as porphyrin (a cyclic tetrapyrrolic structure wherein the four pyrrole rings are joined through four methene bridges, i.e.=Cxe2x88x92) at the centre of which is bound a magnesium atom. Commercial chlorophyll is normally an intensely dark-green aqueous, alcoholic or oil solution, substantially containing chlorophyll a and chlorophyll b, i.e. the two variants that are found (in the approximate ratio of 3:1) in higher plants and in green algae. The most common uses of chlorophyll are in the production of soaps, oils, cosmetics and perfumes, as well as in the food industry, for the production of liquors and confectionery.
xe2x80x9cThe porphyrin structure of chlorophyll is the same found in heme, i.e. the prosthetic group of hemoglobin, wherein at the center of the molecule an atom of iron is present instead of the magnesium atom. It is, very likely, this similitude to the complex responsible for the cellular respiration that accounts for the interesting physiological properties of chlorophyll and, in particular, for its activity as promoter of the cutaneous restoration processes. It is to be noted, in addition, that one of the two carboxy groups pending from the porphyrin structure is esterified, in chlorophyll, with an unsaturated alcohol known as phytol. The latter is a constituent of vitamin E, the therapeutic properties of which are well-known.xe2x80x9d
An alkaline hydrolysis of chlorophyll in mild conditions causes the opening of the cyclopentanone ring present in the molecule and the replacement of both ester groups present (one of which is esterified with phytol) with alkaline metal ions. The corresponding derivatives, known as chlorophyllins, have been proposed as well for the treatment of ulcerative lesions and burns, especially in the presence of concomitant infection. Examples of such indication are found in the U.S. Pat. Nos. 2,120,667 and 2,729,7586.
With reference to the use of chlorophyll in preparations for the treatment of burns and sunburns, the U.S. Pat. No. 3,949,071 proposes the application to the injured skin area of a buffer solution having a pH value of 8-10 containing a base, preferably consisting of an alkaline metal carbonate; one or more surface-active agents; a mixture of unsaturated fatty acids; a volatile agent such as diethyl ether, the evaporation of which is supposed to cause some relief to the burnt skin and, as the proper active ingredients, eugenol, i.e. an essential oil known for its antiseptic properties, and chlorophyll. The latter, according to the disclosure, is believed to cause pigment production and thus contribute to the formation of a secondary protectant in the skin.
In view of the foregoing, the object of the present invention is to provide a preparation particularly suitable for the therapy of burns and sunburns, and also effective on the other types of cutaneous lesions and affections referred to above, which preparation is markedly active in promoting the reparative processes of the skin tissuesxe2x80x94thanks to the presence of chlorophyllxe2x80x94and is, in addition, capable of performing all of the other actions that are requested to a medicinal product for the therapy of burns. Among these actions, the pain relieving and refreshing action and the antimicrobial action are of a major importance.
To achieve such purpose, the present invention proposes to add to chlorophyll some other natural active ingredients the combination of which results in a product of greatly enhanced activity and rapidity of action. The first one of the said additional ingredients is cod liver oil, the activity of which as healing promoter is known (see Merck Index, loc. cit., monograph No. 2464). Cod liver oil is obtained by extraction under pressure from the livers of fishes of the Gadidae species, and is substantially composed of fatty acids glycerides, specifically glycerides of palmitic, stearic, myristic and ricinoleic acid, of cholesterol and of remarkable amounts of vitamins A and D. The commercial product varies in colour from pale-yellow to brown, and has characteristic odour and taste, which become stronger and disagreeable on prolonged exposure to light and air.
Cod liver oil is traditionally used in medicine as a source of vitamins A and D, and is also employed, mainly in veterinary medicine, as a promoter of tissue healing. Such activity, however, does not appear to have been exploited in topical preparations for the treatment of burns and scalds.
According to the invention, the preparation also contains, as a primary ingredient, camphor or 2-bornanone (see Merck Index, loc. cit., monograph No. 1738) a cyclic ketone that is traditionally extracted from the wood (and also from the leaves and the roots) of the camphor tree (Cinnamomum camphora), by steam distillation. Once cooled, the essence crystallises to give a white mass, that is separated from the remaining aqueous liquid by filtration; by treating the said mass under mild pressure and temperature conditions an oil is separated, and the raw camphor is obtained as the residual solid, in the form of brown pieces. The latter is transformed into the commercial camphor by sublimation. Natural camphor consists of the D(+) isomer, that is the biologically active isomer. However, for industrial uses the racemic form, produced synthetically (e.g., from pinene), is also widespread.
Camphor is currently employed for several applications, such as the production of moth repellents and deodorant mixtures, and the manufacture of plastics (especially celluloid), lacquers and varnishes, where it is added as a plasticiser. In the field of phytotherapy camphor is used as a liniment for the treatment of muscular and arthritic pain, as a mucolytic and antispasmodic agent for the upper respiratory tract infections and as a tonic for the circulatory system. The acknowledged pharmacological activities of camphor are on one hand the activity as a topical anaesthetic and analgesic (e.g., against itching and irritation) and, on the other hand, the antiseptic and anti-infective activity. Both the foregoing properties are found to be extremely advantageous for the purposes of the present invention.
Accordingly, the present invention specifically provides a composition for the treatment of burns, sunburns, abrasions, ulcers and cutaneous irritation comprising, as active ingredients, chlorophyll, cod liver oil and camphor in a pharmaceutically acceptable vehicle for topical application. The preferred amounts of the said three main ingredients are from 0.5 to 5 percent by weight of chlorophyll, from 5 to 10 percent by weight of cod liver oil and from 5 to 10 percent by weight of camphor.
Preferably, the proposed composition comprises further ingredients with antiseptic activity, specifically one or both the natural essences known as niaouli oil and thyme oil. Niaouli oil is an essential oil obtained by steam distillation from the fresh leaves of Melaleuca viridiflora, the main components of which are 1,8-cineole, xcex1-terpineol, xcex1-pinene and limonene. Such essence is also known commercially as gomenol, and is used in the disorders of the upper respiratory tract, as a balsamic and expectorant agent and, above all, as an anti-infective agent.
Thymus is in turn an active ingredient obtained from the dried leaves and flowers of Thymus vulgaris (common thyme) and of Thymus zygis (Spanish thyme), each taken separately or mixed together. The essential oil and the dried herb contain as the active ingredient thymol, which is known to be active as an antiseptic of the respiratory tract, for use both in topic preparations (administration by inhalation or instillation) and in preparations for systemic use (oral administration).
According to some specific embodiments, the composition of the invention comprises the three main ingredients in the proportions specified above and, in addition, from 5 to 10 percent by weight of niaouli oil and from 2 to 5 percent by weight of thyme oil.
A preferred formulation of the composition according to the invention is as follows (all of the percentages being by weight):
The non-active carriers or excipients may be chosen among the products conventionally employed in the pharmaceutical art for the formulation of products for topical application. In particular, one or more of the following ingredients may be used: anhydrous lanolin, paraffin, white wax, sweet almond oil, boric acid and/or salts thereof, mono-, di- and triglycerides of fatty acids, non-ionic surfactants and polyethylene glycol. Among the excipients there may be advantageously added, in particular, calendula oil. This product is known to be active in softening and protecting the skin. According to some specific embodiments of the invention the excipient exclusively consists of anhydrous lanolin, while according to other embodiments the said excipient is a mixture of boric acid, paraffin, white wax and sweet almond oil.
The composition according to the invention may be produced in the pharmaceutical forms commonly employed for the therapy of burns and cutaneous lesions, such as ointments, salves, creams, emulsions or gels. The different forms are obtained by appropriately choosing the nature and the proportions of the excipients. The composition of the invention may also be marketed in the form of medicated dressings or bandages.
In use, the product should be spread in a uniform layer on the injured area, and the application should be repeated two or three times a day by adding a thin layer of ointment from the exterior of the dressing, without removing the latter, if possible, for 24 hours.
A specific embodiment of the invention is described for merely illustrative purposes, together with the results of the experimentation carried out on the composition of the invention.